This paper reports on the design and performance of a new Variable Coded Modulation (VCM) system. This VCM system comprises eight of NASA's recommended codes from the Consultative Committee for Space Data Systems (CCSDS) standards, including four turbo and four AR4JA/C2 lowdensity parity-check codes, together with six modulations types (BPSK, QPSK, 8-PSK, 16-APSK, 32-APSK, 64-APSK). The signaling protocol for the transmission mode is based on a CCSDS recommendation. The coded modulation may be dynamically chosen, block to block, to optimize throughput.A novel aspect of the VCM design is that each operating mode has a unique number of symbols in its frame. This enables the receiver to identify the code and modulation simply from the number of symbols occurring between the dedicated frame markers which occur between frames, without having to explicitly transmit a signal to identify the operating mode. This concept allows for a limitless selection of modes and low complexity design.The paper describes a MATLAB end-to-end simulation consisting of random data generation, encoding the data, modulation of the data, additive white Gaussian noise for channel simulation, frame marker identification, coded modulation mode extraction, demodulation, and decoding. Achievable error rates and total throughput are recorded. This simulation can be applied to any link budget that describes the signal to noise ratio over time and can selectively use all or some of the supported coded modulation modes.The simulations show that for a representative low-Earth orbit satellite which encounters a 15 dB variation of symbol SNRs in a 10 minute pass, VCM doubles the achievable throughput, compared to the optimal fixed-mode communication. This simulation shows that VCM is a major and practical method for communicating high data volumes from space.